Audio glitch reduction

In real-time communication applications, the end-to-end latency from mouth to ear is desired to be kept at a minimum. As a result, the application strives to cut out any audio pipeline buffering in the system. On the other hand, the audio device is typically driven by a clock independent of a main clock of the system (e.g. the processor clock) and requires buffering to ensure uninterrupted audio rendering. If the main clock is blocked for any reason, then the application does not have enough time to fill the rendering buffer before the audio device picks up the data in the buffer to feed to the digital-to-analog converter. This result is termed an audio glitch.

To ensure smooth playback, buffering is necessary for the rendering device contradicting the requirement for low latency. A majority of real-time applications choose a buffering length that is a trade-off between latency and expected frequency of glitches. When a glitch happens, the rendering device picks up whatever data was in the buffer. Usually, but not necessarily, that buffer is implemented as a circular buffer. The buffer is usually pre-cleared such that when a glitch happens, then predictable zero-level audio is played out.

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter.

Embodiments are directed to reducing glitch in an audio application by pre-filling a rendering buffer with fake audio that may be a copy of a portion of previously received audio signal or a stretched signal based on previously received audio. If a glitch actually occurs, the buffered signal may be used in place of missing audio signal by smoothing a transition from the fake audio signal to the real audio signal. The fake audio signal may also be simply copied in place of the missing audio to reduce needed buffer space. Potential discontinuities between real and fake audio signals may also be smoothed employing various transition techniques.

These and other features and advantages will be apparent from a reading of the following detailed description and a review of the associated drawings. It is to be understood that both the foregoing general description and the following detailed description are explanatory only and are not restrictive of aspects as claimed.